Imagine an app like Tinder but not for dating. It connects people in the same city/town/country, not based on exact location. So just one broad location check e.g. on app start-up is enough.
If I only need these 3 levels of location (city/town/country), do I still need to go with usual APIs like Geolocation API or Core Location? Or is there a way to simplify it, since no such granularity is needed.
Or would trying to simplify it only lead to more custom work?
Related
I'm writing a web service using Rails where ads can be posted by users. These ads can have location data attached to them, and I'd like to leave the granularity of this open to user choice, so they can add an exact location, or just town/city.
I was planning on using PostGIS, but as far as I can see it only allows exact points to be saved. Is there a way around this, an alternative solution, or do I simply need to abstract this myself?
Thanks.
I'm working with a project its related to Offline map application.Because of that I searched for offline map which shows the defined area. I used MapBox for offline mapping. I can add annotation on this map and draw lines.
But my requirement is offline map with routing. I was fed up to find a offline routing library or offline routing engine to embedded to Xcode.
Appreciate if any of you have any clue or sample project/code to implement this
Note : This question is related to my one. No one replied to this as well
Thanks.
Offline implies no internet, the iPhone is still able in most cases to get the users current location from the GPS. That means that you can be quite confidant that you can find out the current location of the user whilst offline.
The problem with offline routing is that the Phone is dumb, it only remembers the x amount of MB of data in terms of tiles to display.
Routing is something completely different, it takes a point A and B and works out the shortest, fastest, cheapest or all of those between A and B.
This takes a lot more then tiles to accomplish, after all if you think in terms of MVC, tiles are just the dump views, they don't know much about what's around them except what's inside of them. It would be the "controller" who would calculate routes, and for that you would need to be in possession of all the data spanning the desired area for routing.
For each mapping service you will find a different route, maybe not in terms of actual path, but in estimated time, effort etc, what this means is that if you have your own maps (offline in a database), it's up to you to use that data, so you should make your own routing algorithm which I'm sure isn't what you want to do.
So what are your options? At the moment this just isn't possible in the scope you want. Even if you had an offline maps database, you still need a routing algorithm.
In offline case also you can get the current location by using only GPS and you can draw overlay lines from current location to the interesting point for that you have to do some calculations
You can make offline routing by using graphhopper library by making graph data which contains (Street names, routes,edges) . Graph data is taken by .pbf file which can be taken by (Use this:http://download.geofabrik.de) and use commands(in Terminal) that was given by (https://github.com/graphhopper/graphhopper-ios/tree/master/graphhopper-ios-sample) to convert .pbf into graph data. Then we can make offline routing with its instruction (All given in graphhopper iOS sample).please refer that carefully. because i have done and finish my project successfully.
I am developing iOS 5 app which I want to communicate with server providing information about the nearby places for a given location: places locations and annotations. I want to use MapKit to populate my map with this information.
I didn't find any straightforward information regarding the following questions:
Does MapKit has tiles functionality (Google Maps way) out-of-the-box and do I need to work on it additionally, if not?
What is the best practice of retrieving places information (markers positions and annotations) from server?
Is it possible to cache this information so an user can see the nearby places of "his city" in offline mode?
Actually questions 2 and 3 are interrelated: they both address the problem of not retrieving an information (locations + annotations) that is already on map multiple times.
Hopefully I am not overlooking something obvious here.
Thanks!
Update 1: (Regarding places, not maps) More specifically I am interested in, how should I create a "hand-crafted" logical tiles for regions containing the places I fetch from the server, so they would not require refetching themselves when user scrolls the map? I know I can dive into implementing this functionality myself. For example, should I write the places just fetched to a local storage using Core Data immediately after fetching them or organize some queue? Or how could I know when I need to perform a request about the specific region on server and when I just fetch local data that is already on the device? I just want to know, are there any recommended approaches, best practices? Hopefully, I wrote it clear here.
Update 2: I am wondering about best practices here (links, example) not to start creating all this (points 2+3) from scratch. Are there any frameworks incapsulating this or good tutorials?
#Stanislaw - We have implemented the functionality you describe in an app called PreventConnect for one of our clients. The client already had some data stored out in a Google Fusion table. We extended their existing solution by adding another Google Fusion table which stores the geocoordinates for a number of locations. All this being said, to answer your questions...
1) The map portion itself is pretty out of the box, the tiles and what not, but you'll need to do some coding to get zoom extents, pin drops, annotations, and things like that working the way you expect them to work.
2) We found the Google Fusion solution to be quite effective. If you don't want to use Google Fusion there are other cloud database providers like StackMob, database.com, and many others. Google is free and they have an iOS SDK that makes communicating with Google Fusion pretty simple.
3) Absolutely! We cache much of the data in a Core Data store locally on the device. This greatly improves performance and responsiveness.
Time to write a solid answer to this my question (I could have it written a year ago but somehow I lost it from my mind).
Does MapKit has tiles functionality (Google Maps way) out-of-the-box and do I need to work on it additionally, if not?
The answer is yes: MapKit does have it. The keywords here are overlays (MKOverlay, MKOverlayView and others). See my another answer.
See also:
WWDC 2010 Session: Customizing Maps with Overlays,
Apple-WWDC10-TileMap.
What is the best practice of retrieving places information (markers positions and annotations) from server?
Actually since then I didn't learn a lot about "best practices" - unfortunately, nobody told me about them :( - that is why I will describe "my practices".
First of all, there are two strategies of populating a MapKit map with places:
The first strategy is about populating your map with the places by demand: imagine you want to display and see all places nearby (for example, no more than 1km from current user location) - this approach assumes that you ask your server only the places for the box you are being interested in. It means something like: "if I am in Berlin (and I expect 200 places for Berlin), why should I ever fetch the places from Russia, Japan, ... (10000+ places)".
This approach leads to relying on "tiles" functionality that question N1 address: Google maps and Apple maps are usually drawn using 'tiles' so for your "Berlin" portion of map you rely on corresponding "Berlin" tiles that are drawn by MKMapView - you use their dimensions, to ask your server only the places within the "Berlin" box (see my linked answer and the demo app there).
Initially this was the approach I've used and my implementation worked perfectly but later I was pushed to use second approach (see below) because the problem of clustering appeared.
The second strategy is to fetch all the places at once (yeah, all this 10000+ or more) and use Core Data to fetch the places needed for the visible portions of map your are interested in.
Second approach means, that during the first run you send your server a request to fetch all places (I have about 2000 in my app). Important here is that you restrict the fields you fetch to only geo-ones that you really need for your map: id, latitude, longitude.
This 'fetch-all' fetch has a significant impact on my app's first start time (On "the oldest" iPhone 4, I have near 700ms for the whole Fetch + Parse-JSON-into-Core-Data process, and extensive benchmarks show me that it is Core Data and its inserts is a bottleneck) but then you have all the essential geo-info about your places on your device.
Note, that whatever strategy you use, you should do a process of fetching these geo-points efficiently:
Imagine Core Data entity Place which has the following fields structure (preudo-Objective-C code):
// Unique identificator
NSNumber *id,
// Geo info
NSNumber *latitude,
NSNumber *longitude,
// The rest "heavy" info
NSString *name,
NSString *shortDescription,
NSString *detailedDescription, etc
Fetching places efficiently means that you ask only your place records geo-data from your server to make the process of this mirroring as fast as possible.
See also this hot topic: Improve process of mirroring server database to a client database via JSON?.
The clustering problem is out of scope of this question but is still very relevant and affects the whole algorithm you use for the whole proces - the only note I will leave here is that all the current existing clustering solutions will require you to use second strategy - you must have all the places prepared before you run into the clustering algorithms that will organize your places on a map - it means that if you decide to use clustering you must use strategy #2.
Relevant links on clustering:
WWDC 2011 Session: Visualizing Information Geographically with MapKit,
How To Efficiently Display Large Amounts of Data on iOS Maps,
kingpin - Open-source clustering solution: performant and easy-to-use.
Is it possible to cache this information so an user can see the nearby places of "his city" in offline mode?
Yes, both strategies do this: the first one caches the places you see on your map - if you observed Berlin's portion of map you will have Berlin part cached...
When using the second strategy: you will have all essential geo-information about your places cached and ready to be drawn on a map in offline mode (assuming that MapKit cached the map images of regions you browse in offline mode).
I have a Rails 3 app that I'm looking to create in-house analytics for. The items I need to track are impressions (and unique impressions), clicks that come from those impressions, and conversions that come from those clicks. And these are all user-specific so each user can see how many impressions, clicks, and conversions they've received.
What is the best way to go about this? Should I create a separate rails app and call it with pixels? Or should I include all the analytics code in the same app?
Also, are there any analytics platforms already out there that I can customize to meet my needs?
Thanks!
Tim
Before you start re-inventing the wheel, Google Analytics provide a developer API (via OAuth, among other choices) that may provide you with the ability to do what you need (provide each user with a view of their own data).
http://code.google.com/apis/analytics/docs/gdata/home.html
Building your own, while it may seem like an initially basic thing to do, could have serious performance implications further down the line, and Google provide a very detailed view of the the data.
If you really want to write your own, I would strongly urge you not to hit the database for each request you want to track. Keep the data in Redis, or one of the alternatives and periodically persist it to the database via a background task.
If, however, you don't want to put your data into the clutches of our Google Overlord :) then you might indeed consider rolling your own. I have twice before - and I'm doing it again right now: better this time, of course!
If your traffic is not very high and you're running on any decent server platform then adding a tracking system is not going to tax your Rails app noticeably (I know that depends on what 'decent server platform' means but this stuff is pretty cheap these days). Writing to a database is typically very fast - you'd have to have shedloads of clicks to not want to do this straightaway. You can probably bypass most if not all of your before_filters and so on to get a lightning response. One app that runs 2.3.9 uses Metal to do this, for example.
In my new tracking system I have an STI table that goes with models derived from an Activity model; in here you can record both impressions and clicks. Impressions are recorded as the page is built and clicks are recorded using AJAX.
I'm not going to bother with fancy graphs and so on - I'm happy with raw numbers - but these could be added, of course.
At the moment my system is just in the usual app/ folder but I'll probably move it to an engine so I can re-use it more easily.
Hope that helps!
BTW I use Google Analytics as well for a range of sites and it's OK - I just like to do this bit myself.
Depending on how you are going to associate Google Analytics data with a specific user then you might need to double-check the privacy implications. Google doesn't allow their data to be associated with any identifying information about the users being tracked.
If there is a problem then you could try out Piwik as it's open source and you can do what you like with it. It's written in PHP, not Ruby so that might be an issue. As #d11wtq mentions, tracking systems can have performance issues if not built in the right way so you'd be better off starting from something that's already proven to work if possible.
I am working on a mobile mapping application (currently iOS, eventually Android) - and I am struggling with how to best support reverse geocoding from lat/long to Country/State without using an online service.
Apple's reverse geocoding API depends on Google as the backend, and works great while connected. I could achieve similar functionality using the Open Street Maps project too, or any number of other web services.
What I really want however is to create a C library that I can call even when offline from within my application, passing in the GPS coordinates, and having it return the country and/or state at those coordinates. I do not need finer granularity than state-level, so the dataset is not huge.
I've seen examples of how to do this on a server, but never anything appropriate for a mobile device.
I've heard Spatialite might be a solution, but I am not sure how to get it working on iOS, and I wonder if it may be overkill for the problem.
What are some recommended techniques to accomplish this?
Radven
You will need to get the Shapefiles (lat/lng outline) of all the administrative entities (US states, countries, etc). There are a lot of public domain sources for these. For example, the NOAA has shapefiles for US states and territories you can download:
http://www.nws.noaa.gov/geodata/catalog/national/html/us_state.htm
Once you got the shapefiles, you can use a shapefile reader to test if a lat/lng is within a shape. There are open source readers in C, just google. I seen stuff at sourceforge for shapefiles, but have not used these myself.
The Team at OpenGeoCode.Org
If you're looking for an approach based on a quadtree, try Yggdrasil. It generates a quadtree based on country polygon data. A Ruby example script can be found here.
I can suggest good written offline geocoding 3rd party library.
https://github.com/Alterplay/APOfflineReverseGeocoding